https://www.irs.gov/individuals/international-taxpayers/expatriation-tax

https://www.taxesforexpats.com/articles/expatriation/giving-up-us-citizenship-and-the-exit-tax-what-you-need-to-know.html

The exit tax

A critical component for expats to consider when renouncing US citizenship is the Exit Tax.

Essentially, it is a tax on the net unrealized gain on your worldwide assets as if you sold them the day before expatriation.

This tax applies to individuals who meet any of the following criteria:

- Average annual net income tax for the five years ending before the date of expatriation exceeds a specified threshold amount. (150-190k yearly last few years.)

- Net worth is $2 million or more on the date of expatriation.

- Failure to certify compliance with US tax obligations for the five years preceding expatriation.

Even if you are a covered expat, you just have to pay a capital gains at the regular rate for all of your assets as if they were sold 1 day before you escaped.